Two police officers were injured in a tense stand off with fans at Celtic Park.
Police Scotland said the officers received minor injuries in the clashes at the stadium after Celtic were beaten 2-0 at the hands of Ross County in the Betfred Cup.
In a statement, a senior officer blamed the assembled supporters for leaving the officers injured in the clashes.
Superintendent Stevie Dolan, Greater Glasgow Division said: “Around 4.30pm on Sunday, 29 November, a large number of fans started to gather outside Celtic Park to protest.
“An appropriate policing response was carried out and the group has now dispersed. No arrests have been made however two officers sustained minor injuries as a result of the actions of the gathered group.
"We strongly condemn these actions and remind fans that enforcement options remain at our disposal.
“The Scottish Government regulations are clear that protests are prohibited in areas under level four restrictions and we would urge people to find alternative ways to protest to prevent the spread of coronavirus.
“Disorder of any sort will not be tolerated and appropriate action will be taken where any offences are identified.”